The present invention relates to an ink jet recording apparatus in which ink drops are jetted from an electrode of a recording head toward a recording medium, thus recording an image on the recording medium.
As one type of ink jetting operation of an ink jet recording apparatus, which is utilized for directly jetting ink drops from a minute ink jetting unit toward a recording medium for forming dots on the recording medium, there is an electrostatic recording system in which the ink drops are drawn by an electrostatic force. According to the electrostatic recording system, it is possible to control the ink jetting amount by subjecting the voltage applied to the recording electrode to a pulse width modulation. Thus, this system has attracted attention as a system for use in a high definition ink jet printer.
As one example of this type of system, WO-A-9311866 discloses a method in which ink composed of a solvent with a color agent dispersed therein at a low concentration is supplied to a front face of a recording electrode, and the recording electrode is supplied with a voltage to form an electric field, so that the color agent with an electric charge is flocculated, thus densely concentrated ink is jetted from the recording electrode toward the recording medium.
On the other hand, WO-A-9727058 discloses a technology in which ink is supplied to a flow path of L-letter shape, having a square cross-section, the flow path being disposed so that a corner thereof is brought to a position nearest to the recording medium, and an electrode having a linear shape provided in the flow path is supplied with a voltage so as to make the ink fly from the L-letter shaped corner position.
Japanese Patent Laid-open No. 10-52919 and the above-mentioned WO-A-9311866 also disclose a technology in which a color agent flocculated material formed around the tip end portion of the recording electrode during bias voltage application is jetted toward the recording medium by applying thereto a pulse voltage corresponding to image information in a superimposing manner. The technology disclosed in these gazettes does not require use of a jetting device having a nozzle aperture which tends to cause ink clogging. Thus, according to these technologies, it becomes possible to realize an ink jet recording apparatus which has an excellent ink jetting stability.